The present invention relates generally to a plurality of printers connected to a computer network and more particularly a printer system for connecting a secondary printer to a network by connection to a primary printer.
Office data processing environments typically have a large number of computer users and a lesser number of printers to which the users require access. The most desirable architecture for configuring users and printers is one in which an arbitrary number of users may have access to any desired printer in order to provide the most efficient and economical use of the printer resources.
Commercial networking products are available for coupling together a plurality of computers with peripheral devices such as printers to provide the desired communication flexibility and sharing of printer resources. Examples of network connection systems for interconnecting computers and printers include token ring networks conforming to IEEE Std. 802.5 with interconnection speeds up to 16 Megabits per second, and networks based on Ethernet technology conforming to IEEE Std 802.3, with interconnection speeds up to 100 Megabits per second. Typically printers (and other devices) employ network interface units (NIU) for connecting to the network connection system. Because of the high speed of data transmission on the network interconnection system and the complexity of the data protocols for operating with the network, the cost of NIUs for attaching printers to a network is significantly higher than the cost of point-to-point interface units dedicating a printer to a specific computer.
Efficient use of printers on a network also requires a print manager. The print manager is typically a separate computer attached to the network connection system. By receiving all print jobs prior to transmission to a designated printer, the print manager mediates the print jobs originating from multiple network devices attempting to simultaneously access the same printer. The print manager also provides storage for the printer data and queues the print jobs for processing by the designated printer in accordance with the printer""s printing and data storage capacity. Since generally, printers have only a limited memory capacity, many print jobs require repeated access to the print manager for transfer of the entire print job to the printer. This is inefficient because of complex network protocols having to be repeatedly executed and the sharing of the network connection system with other data being transferred.
In the case of printers, the rate at which data can be printed on an individual printer is generally small compared to the capacity of the network interface unit for transferring data from the network connection system to the printer. Thus, a typical network interface unit has the capacity to support a multiplicity of printers.
It would be desirable to be able to functionally connect multiple printers to a network without requiring each printer to have a dedicated network interface unit. Further, it would be desirable if each printer did not require the complex software to support high level printer languages and the extensive memory required to efficiently print large print jobs.
A recent development is stand-alone print server devices, such as the Hewlett Packard DEP1233, which provides the capability of connecting up to three printers having point-to-point interfaces to a single physical point on a network. However, while stand alone print servers allow non network-compatible printers to be attached to a network, stand-alone print servers do not reduce the complexity in the printer software or relax printer memory requirements.
The present invention is directed to a primary printer having a network interface and capable of supporting one or more non-network compatible secondary printers connected to the primary printer such that each secondary printer appears to a user to be directly connected to the network. Significant savings in secondary printer hardware and software costs are achievable by incorporating functions normally replicated in each secondary printer into the primary printer and utilizing a simple point-to-point data communication interface between the primary printer and each secondary printer. The primary printer may also function as a print manager for the attached secondary printers by simple addition of a mass storage device. Cost savings in the network are possible because of the reduced number of network hardware nodes.
Briefly stated the present invention is a printer system for printing data from a network device connected to a network connection system. The printer system comprises a primary printer coupled to the network connection system by a network interface unit and a secondary printer coupled to the primary printer by a secondary non-network interface unit. The primary printer routes the data received from the network connection system to one of the primary printer and the secondary printer for printing, making the secondary printer appear to a user of the network device to be directly connected to the network connection system.
The present invention further comprises a primary printer connected to a network connection system for printing data from a network device connected to the network connection system and for providing the data to a secondary printer. The primary printer comprises a network interface unit for receiving and transmitting the data from the network device and outputting status data to the network device representative of the status of the primary printer and the secondary printer. The primary printer also includes a primary print engine, a processor for receiving the data transmitted from the network interface unit and for transmitting the data to one of the primary print engine and the secondary printer and a primary non-network interface connected between the processor and the secondary printer, for providing data to the secondary printer when designated by the processor and for receiving status data from the secondary printer. The secondary printer appears to a user of the network device to be directly connected to the network connection system.
The present invention further comprises a secondary printer for connection to a primary printer. The secondary printer comprises a secondary non-network interface unit for receiving and transmitting non-printer specific data received from the primary printer and for outputting status data to the primary printer, a processor connected to the secondary non-network interface for translating the non-printer specific data to print engine compatible data and a secondary print engine for receiving the print engine compatible data from the processor and for printing the print engine compatible data.
The present invention further comprises a method for printing data from one or more network devices connected to a network connection system on a primary printer connected to the network connection system and a secondary printer connected to the primary printer. The method includes receiving a print job request by the primary printer from the network device, receiving the data in the primary printer connected to the network connection system, transmitting the data to either a primary print engine or the secondary printer and printing the data in either the primary printer or the secondary printer.
The present invention further comprises a method for determining an operational status of a secondary printer by a network device connected to the network connection system in which the secondary printer is connected to the network connection system by a primary printer. The method includes the steps of transmitting a status request from the network device to the primary printer, receiving the status request in the primary printer and responding to the network device with status data representative of the operational status of the secondary printer.